1. Field of the Invention
The present invention relates to a display device and a method of manufacturing the display device. More particularly, example embodiments of the present invention relate to a display device manufactured by using an etchant composition for etching a copper alloy and an oxide semiconductor simultaneously in a photolithography process, and a method of manufacturing the display device.
2. Description of the Related Art
In general, a liquid crystal display (LCD) panel includes a display substrate, an opposite substrate facing the display substrate, and a liquid crystal layer interposed between the display substrate and the opposite substrate. The display substrate includes a switching element and a pixel electrode. A voltage is applied to the liquid crystal layer to control the transmittance of light through the liquid crystal layer so that an image is displayed.
The display substrate includes a plurality of thin-film layer patterns, which are formed by using a photolithography process to pattern a thin-film layer formed on an insulating substrate. For example, a photoresist pattern is formed on the thin-film layer, and then the thin-film layer is etched using the photoresist pattern as an etching mask, so that the thin-film layer patterns are formed. The thin-film layer may be etched through a wet-etching process or a dry-etching process according to properties of the thin-film layer. For example, when the thin-film layer includes a metal, the thin-film layer may be etched through a wet-etching process using an etchant solution. When the thin-film layer is an insulating layer including silicon oxide, etc., the thin-film layer may be etched through a dry-etching process using an etching gas.
In order to form a thin-film layer pattern, a mask having a design corresponding to the thin-film layer pattern is used. Recently, methods are in development which may allow thin-film layer patterns having different shapes to be formed by one mask. Using a single mask may simplify manufacturing processes, and may reduce the number of masks, which are expensive, required to form the thin-film layer patterns. When, however, thin-film layers are chemically different from each other, the thin-film layers need to be etched by individual etching processes, respectively. Thus, it is difficult to reduce numbers of processes or masks in such circumstances.
Copper has a high electric conductivity, and copper is an abundant natural resource. Copper may form a low-resistance line as compared to aluminum, chromium, etc. However, when a lower layer formed under a copper layer includes an oxygen atom, adhesion between the copper layer and the lower layer is reduced, so that employing a copper layer can be difficult in practice.